The present invention relates to a coin discriminating apparatus and, particularly, such an apparatus for detecting the surface pattern of a coin and discriminating whether or not the coin is acceptable and the denomination of the coin.
Conventionally, it is discriminated whether or not coins are acceptable, namely, whether coins are genuine or counterfeit and whether or not coins are current coins by detecting the diameters, materials, thickness and the like of coins. However, a coin discriminating apparatus for discriminating coins by optically detecting coin surface patterns has been recently proposed in order to improve discriminating accuracy.
For example, Japanese Patent Application Laid-Open No. 8-36661 proposes a coin discriminating apparatus which optically detects the surface pattern of a coin using a CCD area sensor and compares the detected pattern with reference patterns, thereby discriminating the denomination of the coin and whether or not the coin is acceptable.
However, in the case where the surface pattern of a coin is detected using a CCD area sensor and the coin is discriminated, the coin discriminating apparatus inevitably becomes large and costly.
It is also conceivable to constitute a coin discriminating apparatus by disposing light emitting elements in an annular manner on the side of a line sensor, detecting light reflected by a coin by the line sensor, detecting the diameter of the coin as well as the surface pattern of the coin, tentatively determining the denomination of the coin based on the diameter of the coin, reading the reference surface pattern of coins of the tentatively determined denomination stored in a memory, comparing the reference surface pattern with the surface pattern of the coin detected by the line sensor, and discriminating the coin.
However, in the thus constituted coin discriminating apparatus, since the positional relationships between the respective edge portions of coins and the respective light emitting elements are not constant, it is difficult to produce the surface pattern data of the coin with high accuracy. Therefore, it is difficult to tentatively determine the denomination of the coin based on the diameter of the coin with high accuracy to reliably select the reference surface pattern data to be compared with the surface pattern data of the coin and, accordingly, it is impossible to discriminate based on the surface pattern data of the coin whether or not the coin is acceptable and the denomination of the coin with high accuracy.
It is therefore an object of the present invention to provide a compact coin discriminating apparatus which can discriminate coins with high accuracy and can be manufactured at low cost.
The above and other objects of the present invention can be accomplished by a coin discriminating apparatus comprising light emitting means for emitting light toward one surface of a coin being transported, a line sensor for photoelectrically detecting light emitted from the light emitting means and reflected by the one surface of the coin and producing image pattern data of the one surface of the coin, reference data storing means for storing reference data of coins of each denomination, first denomination determining means for calculating a diameter of the coin based on the image pattern data of the one surface of the coin produced by the line sensor, comparing the thus calculated diameter of the coin with reference diameter data of coins of each denomination stored in the reference data storing means and preliminarily determining the denomination of the coin, and denomination discriminating means for reading reference pattern data of coins of the denomination determined by the first denomination determining means from the reference data storing means, comparing the thus read reference pattern data with image pattern data of the one surface of the coin and finally determining the denomination of the coin, the light emitting means including a plurality of light emitting elements and at least 70% of the light emitting elements being disposed on straight lines connecting the center of a reference coin and points where a periphery of the reference coin crosses the line sensor and at positions equidistant from the center of the reference coin by the same distance L.
According to the present invention, at least 70% of the light emitting elements are disposed on straight lines connecting the center of a reference coin and points where a periphery of the reference coin crosses the line sensor and at positions equidistant from the center of the reference coin. The peripheral points of the coin can therefore be illuminated with light emitted from the light emitting elements under substantially the same conditions. Therefore, since a clear image can be produced by the line sensor, it is possible to discriminate the denomination of the coin with high accuracy based on the diameter of the coin and also discriminate the denomination of the coin with high accuracy by pattern-matching the image pattern data of the coin and the reference pattern data.
In a preferred aspect of the present invention, the diameter of the reference coin is set to be equal to an average diameter of coins to be handled.
In another preferred aspect of the present invention, the diameter of the reference coin is set to be an intermediate of the diameters of coins to be handled.
In a further preferred aspect of the present invention, at least 80% of the light emitting elements are disposed on straight lines connecting the center of a reference coin and points where the periphery of the reference coin crosses the line sensor and at positions equidistant from the center of the reference coin.
According to the this further preferred aspect of the present invention, the respective peripheral points of the coin can be illuminated with light emitted from the light emitting elements under still more uniform conditions. Since a clear image can therefore be produced by the line sensor, it is possible to discriminate the denomination of the coin with high accuracy based on the diameter of the coin and also discriminate the denomination of the coin with high accuracy by pattern-matching the image pattern data of the coin and the reference pattern data.
In a further preferred aspect of the present invention, the coin discriminating apparatus further includes magnetic sensor means for detecting magnetic properties of the coin and second denomination determining means for determining the denomination of the coin based on the magnetic properties of the coin detected by the magnetic sensor means, the denomination discriminating means being constituted so as to discriminate that the coin is an unacceptable coin when the denomination of the coin determined by the first denomination determining means and the denomination of the coin determined by the second denomination determining means do not coincide.
According to this further preferred aspect of the present invention, since the denomination of the coin is discriminated considering the magnetic properties of the coin, the discrimination accuracy can be further improved.
The above and other objects and features of the present invention will become apparent from the following description made with reference to the accompanying drawings.